At least 39 people were killed and dozens injured after an illegal, half-constructed building collapsed in seconds "like a pack of cards" on the outskirts of India's financial centre Mumbai, officials and witnesses said.
Rescue workers using cranes and bulldozers searched for survivors in the wreck of steel and concrete yesterday after the seven-storey building crumbled on Thursday night.
Residents said labourers paying rent of around $5 a day had lived in it.
A shortage of cheap homes in Asia's third-largest economy has led to a rise in illegal construction by developers who use substandard materials and shoddy methods in order to offer rock-bottom rents to low-paid workers.
"The building collapsed like a pack of cards within three to four seconds," said Ramlal, a local resident. "It just tilted a bit and collapsed," he said.
The building, which was in a forested area in the city of Thane, had been made using poor materials and without proper approvals, said Sandeep Malvi, a spokesman for licensing authority the Thane Municipal Corporation.
He said 39 people had been killed and 69 injured. Indian media quoted officials giving higher death tolls.
Rescue workers pulled an infant alive from the rubble as they used jackhammers and other equipment to cut through metal and concrete in their hunt for survivors.
Police said they were searching for the builders and would charge them with culpable homicide in connection with the disaster.
Building collapses are a common occurrence in India, where a booming economy and rising real estate prices has led often unauthorised multi-storey structures to mushroom on the outskirts of cities and towns.
In one of the worst such accidents of recent years, 69 people died and more than 80 were injured in November 2010 in New Delhi where a residential building under construction collapsed, trapping families in the lower floors.